But with obesity now labeled a national public health menace, more chains are trying to clean up their acts and seize on customers' changing dietary needs as a marketing opportunity.

The Food Marketing Institute even staged its second-ever health and wellness conference Monday in Orlando for big chains to swap notes and solicit suggestions from health experts.

For years, grocers mostly gave lip service to the subject by dishing out more healthful choices and passing out recipes. But now that obesity afflicts a third of all Americans and childhood obesity is considered an epidemic, more stores have gotten religion about teaching nutrition and becoming a resource for diet and disease management.

"The obesity issue is making grocers re-evaluate their role in public health," said Susan Borra, a dietitian who is the trade group's senior vice president of communications. She sees tighter food ingredient labeling dispatching more bad-for-you additives like sodium and added sugars, the way it did away with trans fats.

It's a delicate balancing act for mass-market grocers. They stock what customers like to buy. While public health advocates want people to consume less, grocers are in business to sell more. They pocket most of their marketing money from the soda, processed foods and meat industries.

But they can't ignore the public push, experts told them.

"It's imperative supermarkets get ahead of this trend, partly because Walgreens and CVS already have laid claim to being the health stores," said Phil Lempert, a marketing consultant who calls himself the Supermarket Guru, noting that nutrition and diet rank up there with taste and price in shaping today's shopping lists.

Some Tampa Bay grocers led the trend. Sweetbay Supermarket's Guiding Stars nutritional shelf tags are being copied nationally. Publix Super Markets months ago started marketing its pharmacies as a disease management resource for diabetics. Winn-Dixie Stores, which offers free scheduled glucose and cholesterol screening and diet advice from pharmacists, is working on several similar initiatives.

Skogen's Festival Foods in Wisconsin posts dietitians in stores to dole out meal planning advice and lead tours to pinpoint healthy foods. In Indiana, Marsh Supermarkets developed lesson plans to teach nutrition to fourth-graders in 350 schools and promotes them with star NFL quarterback Peyton Manning in partnership with a children's hospital.

Diet advice is a big enough new market that LearnSomething, a Tallahassee firm, just developed 17 online training modules for supermarket pharmacists and nurse practitioners.

It's also marketing shelf tags to guide shoppers on disease-specific diets with codes that can be read by smart phones.

"The grocery store is in the sweet spot to market healthy foods and reverse childhood obesity," said Tracy Orleans, a clinical psychologist with the Robert Wood Johnson Foundation, which promotes healthy foods, diet and physical activity to prevent chronic disease and childhood obesity.

How overweight are Americans? Enough that 80 million are insulin-resistant, a precursor of diabetes, and the number of diabetics is forecast to rise by 11 million to 37 million in five years.

Meanwhile, 20 percent of children are severely overweight, putting them at risk for mature adult disease like diabetes by their late teens, said Dr. David Katz, director of the Yale Prevention Research Center. He fears it will be the first American generation of kids who live shorter lives than their parents.

It's no wonder, given the average American's sedentary lifestyle and a diet that is 65 percent processed foods and 25 percent animal products, said Bryant Terry, a Memphis-born food activist chef and author of Vegan Soul Kitchen. He said he wrote the book not because he's vegan, but to show "that not all African-American cuisine is animal fat."

"People need more plants in their diet," he said.

Katz recommended supermarkets team up with health insurers to offer reward-point programs to shoppers who buy healthy foods. And he said foodmakers should stop creating misleading labels that make it harder to make informed choices. He found a reduced-fat peanut butter that packed more sugar and half the fiber of the regular version.

"My wife is a Ph.D. neuroscientist, and even she has given up trying to figure out the best bread to eat by reading ingredient labels," he said.

Mark Albright can be reached at albright@sptimes.com or (727) 892-8252.